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(No Model.)

R. HOWARTH.

NUT LOCK. A y No. 321,500. Patented Juy 7, 1885.

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limiten States ROBERT HOWYARTH, OF VOLVERHi-XMPTN, COUNTY 0E SPAlf`FORD,ENG- LAND, ASSIGNOR TO MOSES BAYLlSS, EDVIN JONES, WILLIAM lAYLlSS,SAMUEL BAYLTSS, AND YILLIAM EDWIN JONES.

NUTHLOCK,

To CLZZ whom 'it may concern:

Be it known that I, ROBERT HOWARTH, a subject ot' the Queen of GreatBritain, residing at Volverhainpton, in thc county et' Stafford,England, have invented certain new and useful improvements in means forpreventing nuts and bolts or other screwed parts frein working loose,(for which invention Letters Patent have heen applied for iu England,the application heing dated the 12th danyv of May, 1884:, and numbered7,539, hut such Letters Patent have not yet been granted.) ot' which thefollowing is a speciticatiou.

The niain purpose ofthis invention is i o forni a nut for screw-bolts(and for other articles haring aniale or external screw thread) in suolia manner as that thc nut shall distort the convolntions of the threadupon the screwbolt as the saine pass through the part oi" the nutadjacent to the outer face as the nut is screwed up thereon, suchdistorted convolutions of the thread securely preventing the nut i'roinbecoming unscrewed by any jarring action to which. it may he subjected.

The means by which this invention may he carried into effect areillustrated hy the drawings herewith, of which- Figure l is a transversesection taken diagonally through an ordinary screwed nut, and Fig. 2 aback or outer elevation ofthe sainethat is, ofthe tace a, Fig. l.

A fulleredended tool is driven or pressed against the outer faceoithenut, so as to produce a grooved or prcsseddown part, b, by which incansthe outer convolution or convolutions of the thread are pressed down orin- -dented in one place around their cir-oninterenec with the generalpressing down or indenting of the nietal occasioned by the tool. Thispressing down ofthe outer conrolu tions of the thread is clearly shownat Fig. l. As this nut is afterward screwed upon its loolt (orcorresponding part) the unaltered convolutions ot the thread, beingthose through the greater thickness of the nut, as shown, are readilyscrewed upon the bolt; lout when the presseddown or indented parts coineto be screwed thereon the effect is to distort those convoluti ons ofthe the thread of the holt upon which Ing part of Letters 'Patent No.321,500, dated July 7, 1885.

" Wl'aj IQ, 1R44, No. 7,5%), and in 'Belgium February 12"] i385,

the presseddown or indented conroluiions of the thread of thc/nut arescrewed-thatis to say, such conrolutions of the thread ofthe holt. areforced out ol' pitch or gage with the remaining conrolutions of thethread ci' the holt.

Fig. 3 illustrates the screwed end of a holt upon which a nut withpresseddown or indented convolutions ol' the thread has been screwed upbut not 4screwed hack. rllie nut is omitted in the illustration. l

c shows the distortion in the convolutions of the thread of the holt atthe point up to which a pressed-down or indented convolution ofthethread ofthe nut has heen screwed. Each ot' the outer convolutions otthe thread ot the holt are distorted as a pressed-down or indentedconvolntion of the thread of a nut is screwed up thereon; hut thedistortion shows chiefly at the point up to which a presseddown orindented convolution of the thread of the nut is screwed as theremaining outer convolutions ot' the thread of the holt have beenequally distorted throughout, and show therefore to a regular pitchtogether, although out of true pitch with the remaining convolutions ofthe thread, and also altered in shape therefrom. rlhe nut with thepressed down or indented convolutions ofthe thread is thus securelylocked upon the holt and prevented frein becoming unscrewed hyanyjarring action to which it may be subjected, Theei'fectis ofcoursethesaine whether the nut is screwed up upon the holt or the holtscrewed up within the nut. One or more ot' the convolutious of thethread cfa nut matT ci course he pressed down or indented in anyconvenient nianncr otherwise than simply by the fullered tool reierredto; and the convolution or convolutions may he pressed down or indentedin one only or more places around the circumference, as desired.

Fig. d is a corresponding View to Fig. l. According to this View theouter convolution of the thread of the nut is pressed downward aroundits Aentire circumference by means of a dome-ended tool, the bottoni ofwhich is indicated hy dotted lines.

Fig. :j is a corresponding section to Fig. l,

and Fig. 6 a corresponding view to Fig. 2. In these two figures,however, d is aprojection or lump formed upon the nut-blank.' After thenut has been screwed in the ordinary manner this projection d ishammered or pressed down, as shown at Fig. 7, thus pressing down orindenting the outer convolutions of the thread of the nut with the sameeffect as in the other cases of pressing down or indenting theconvolution or eonvolutions of the thread. One only of these projectionsd or more may be employed, as desired, or a projection may be formedaround the entire circumference of the edge of the hole through the nutat the outer face thereof when forming the nutblank, and this projectionbe hammered or pressed down, so as to press down or indent theconvolution or convolutions of the thread next to the outer face of thenut.

In this specification the expressions pressed down,77 press down, andpressing` down,77 in relation to a convolution or convolutions of athread, refer to the distortion of such convolution or convolutions in adirection parallel, or approximately so,with the axis around which suchthread convolutes, whether such distortion has been or is produced byactual pressing` down or in an analogous manner.

It will be seen that my improved construction of nuts are self-lockingquite independently of any specialA attention on the part of the personwhose duty it may be to screw. them upon their bolts (or correspondingparts) as there are no loose or extra parts thereto to be fixed orplaced in position.

This invention is of course applicable also, as will be readilyunderstood, in the case of deck-plates, of a certain description ofshplates, and various other articles which have a hole or holestherethrough screwed to receive a screwed bolt or bolts or other part orparts having a male or external screw-thread thereon.

Having thus stated the nature of my said invention, and particularlydescribed the man.- ner of performingV the same, I declare that what Iclaim isl. A nut or other analogous article which has internalscrew-threads, having one or more of the convolutions of itsscrew-thread pressed or indented in the direction of the nut-axis,substantially as described, to form a locking device,whereby, when saidnut is screwed onto a bolt or other analagous article having an externalscrew-thread, the indented portion of the thread in the nut will distortor force out of true pitch some portion of the convolutions of thethread on the bolt, as set forth.

2. A nut or other analogous article which has internal screw-threads,having a lump or projection, d, formed on its face, in which a portionof the screw-thread is formed, Whereby, when thislump or projection ishammered down, as described, in the direction of the nut-axis, thethreads of the screw in the nut will be distorted, as and for thepurposes set forth.

In witness whereof I have hereunto signed my name in the presence of twosubscribing Witnesses.

ROBERT HOVARTH.

Vitnesses:

STEPHEN WATKINs, ROBERT M. LIs'rER.

